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Discussion Starter #1
I regularly charge using a vw granny charger at 2kw.

I’m on Agile and sometimes when the rates are very good I would like to charge both my cars at once.

Would using another granny charger off the same double socket be risky? I could probably run my tough leads extension cable from another socket if that would be safer. Though it may not quite reach...
 

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Safer not to use an extension cable and as long as its a double socket in good condition and its on the ring main, not a spur, then it should not be an issue.
 

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The best there is at what I do
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You could potentially be pulling 4kW from the double socket, if your doing this make sure its a good quality socket not a cheap import and make sure its on the ring main not a spur, get yourself a laser temperature thermometer and check how hot it gets when pulling the 4kW then you will know how hot its getting, there are loads of laser thermometers on Ebay like this:

 

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many double sockets are not rated for both outlets running at 13A simultaneously.

BS1363-2:1995 requires for double socket outlets that both socket outlets have loads applied via test plugs, 1 test plug having a load of 14 amps whilst the other has a load of 6 amps, making a total load of 20 amps on the cable supplying the double socket outlet. The double socket outlet is then subjected to this loading for a minimum continuous period of 4 hours or longer until stability is reached with a maximum duration of 8 hours (stability being taken as less than 1 degC rise within 1 h). The test is passed if neither the terminals / terminations, nor the accessible external surface, increase in temperature by more than 52 degC.
Charging from 13A outlets is pretty jank regardless. Fit a proper charge point.
 

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Unlikely the granny pEVSEs will both be running 13A. 10A more likely surely. But deffo needs a good quality socket, and regular temp checks on it. Even better if the OP had pEVSEs that can select 6A , e.g. evconnectors.com one which does 6/8/10/13/16(!) A. pEVSEs will last quite a bit longer if run at lower currents I think. Mine finally expired after 5 years use, but had seen 13A on a few occasions. It got new relays put in at 4 yrs old when first lot started overheating. Replacement is deffo going to be run at the lowest current I can manage!
 

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If it's a double socket on a ring then take care. It's not only that socket involved in the current flow, but also all the other sockets that are daisy chained together on the ring. Any socket could overheat due to a poor connection. And if any socket on the ring has a connection that is not being made then the current can flow only one way round the ring and potentially overload the cable and any other weak connections. I'd get an electrician with a ring main tester to test the ring. I do get the ring mains tested whenever I move house.
 

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And if any socket on the ring has a connection that is not being made then the current can flow only one way round the ring
I've no idea if the recommendation has changed, but many years ago they said you should not cut the cable when looping a ring main - just strip the insulation and then fold the cores to put them in the terminals. This avoids a loose connection affecting the rest of the ring.
Of course hardly anyone ever did that - it takes a little more time, care and skill.
 

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In summary, I think the main advice is that it is not a great idea. You probably realise this, hence the question being asked in the first place. If a fire breaks out 5 minutes after you last checked it, you'll wish you hadn't done it.

Personally, I wouldn't rest if I had 2 chargers running from a double socket like that. I'd have to sit there for hours watching it.

Just get a proper EVSE and keep yourself safe.
 

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Or run them from two separate circuits.
 
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As others have said, I'd say it isn't a great idea unless you can dial both chargers down to 6A. Also, definitely check what else is on using that ring main. My house has 2 downstairs rings, and as luck would have it the one I charge off is not used by any of the high load appliances in the kitchen. Many houses only have 2 ring mains, and if you are charging off the downstairs one then some other quite high load devices are likely to be plugged into it, like kettle, washing machine, dishwasher, tumble drier etc. Even electric heaters too possibly, and some old houses might even have an immersion heater running off one ring too, or a single oven, like my old house did!
I'm still wary of charging my car overnight off the granny, and if I do I tend to charge it from the garage, which isn't attached to the house. There's a good reason why supplied 3 pin chargers tend to be only 10A now, far too much to go wrong using a full on 13A appliance over a long time period!
 

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And (there's always one, isn't there?) I was at my parents' place at the weekend and discovered their house (3 bed semi) has a single ring main for all the sockets in the entire place, including the kitchen. Nothing like the 70s for corner cutting was there? At least it seems to be fitted with a 32A fuse ..
 

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Another question I can thing of which I would ask myself is how long do these ‘cheap’ rates last. If it’s only for a few hours overnight is it worth the risk?
 

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I regularly charge using a vw granny charger at 2kw.

I’m on Agile and sometimes when the rates are very good I would like to charge both my cars at once.

Would using another granny charger off the same double socket be risky? I could probably run my tough leads extension cable from another socket if that would be safer. Though it may not quite reach...
This will end in tears, don't do it.
 

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Another question I can thing of which I would ask myself is how long do these ‘cheap’ rates last. If it’s only for a few hours overnight is it worth the risk?
😂 you clearly haven’t met about 90% of Agile customers who would sell their granny for sub 8p/kWh.
 

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Very true. Ours is 11p/kWh standard rate with Gulf and I definitely would go risking my life to save a couple of pound
I’m not even joking. I’ve seen so many people post about how they’ll avoid cooking dinner because it’s too expensive and will go to great lengths to save a few pence charging their £60k electric car.
 

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Discussion Starter #17
Thanks everyone for the replies, very useful. On reflection, I've decided it's not worth risking the family evacuating the house late at night to smoke alarms going off and possible smoke inhalation. So I'll stick to just running one charger at a time and maybe beef up smoke detection in the garage where it's plugged in. In my defence, it is a very modern electrical install and I got the impression the electrician was good (though I know little myself!). I wouldn't be considering it at all on old electrics, like at my parents house.

Would a plastic socket or plug burning / smouldering set off a smoke alarm positioned on the ceiling above the plug socket? There's already one smoke alarm, which is in the center of the room, about 3m away from the socket. I also get nervous that the gas meter is annoyingly directly above the socket too...

I am put off fitting a outside wall charger, partly because of aesthetics but also we don't do that many miles so occasional granny charging and having two EVs means we usually have enough day to day.
 

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Thanks everyone for the replies, very useful. On reflection, I've decided it's not worth risking the family evacuating the house late at night to smoke alarms going off and possible smoke inhalation. So I'll stick to just running one charger at a time and maybe beef up smoke detection in the garage where it's plugged in. In my defence, it is a very modern electrical install and I got the impression the electrician was good (though I know little myself!). I wouldn't be considering it at all on old electrics, like at my parents house.

Would a plastic socket or plug burning / smouldering set off a smoke alarm positioned on the ceiling above the plug socket? There's already one smoke alarm, which is in the center of the room, about 3m away from the socket. I also get nervous that the gas meter is annoyingly directly above the socket too...

I am put off fitting a outside wall charger, partly because of aesthetics but also we don't do that many miles so occasional granny charging and having two EVs means we usually have enough day to day.
Old or new electrics, you are just kidding yourself. Get a proper EVSE or at very least a CEE socket
 

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Would a plastic socket or plug burning / smouldering set off a smoke alarm positioned on the ceiling above the plug socket?
The socket itself probably wouldn’t burn, the wiring behind it would I should think. But is it worth risking it just to save a few quid? The other thing to keep in mind, if there was a fire because 2 chargers were plugged into the same double socket would your house insurance cover the damage? I’m sure it would invalidate it.
 
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